Solubility of dimethyl-2,6-naphthalene dicarboxylate in acetic acid,N,N-dimethyl acetamide,dimethyl sulphoxide,and N-methyl-2-ketopyrrolidine were determined using a dynamic method.The measured systems were correlated by UNIFAC group contribution method.A new main group (atomatic ester, ACCOO) was defined to express the activity coefficients of the aromatic ester.New interaction parameters of the ACCOO group were expressed as the first-order function of temperature and were determined from the experimental data.The calculated results for the new interaction parameters were satisfactory.The measured systems were also correlated with the Wilson and λ-h models,and the results were compared with those of the UNIFAC model.